Synthesis and Characterization of Proton-Conducting Oxides as Hydrogen Transport Membranes

Abstract

The hydrogen permeation properties of dense SrCe 0.95 Yb 0.05 O 3-x membranes were examined under various conditions and described based on the conductivities of available charge carriers using a transport model for mixed conductors. The chemical environment on each side of the membrane influences not only the chemical potential driving force for transport but also the conductivities of the various charge carriers. When one side of the membrane is exposed to oxidizing atmosphere, the H 2 flux is limited by hole conduction. In reducing atmosphere, SrCe 0.95 Yb 0.05 O 3-x membranes show electron conductivity and the electron transference number increases with increasing H 2 partial pressure. The hydrogen flux-current behavior during electrochemical pumping is caused by an insulatorsemiconductor transition that occurs with increasing applied voltage.

Absorption Kinetics of Hydrogen In Nanocrystals of BaCe0.95Yb0.05O3-δProton-Conducting Perovskite

“…In Table are reported the self-diffusion coefficients, , for hydrogen diffusion in BaCe 0.95 Yb 0.05 O 3 - δ at different temperatures. To calculate , it was necessary to make use of the values of the electronic transference number, reported in literature for mixed proton-electronic conductors, in general, and in particular for the open circuit permeation of hydrogen in a SrCe 0.95 Yb 0.05 O 3 - δ perovskite, that is, a material very similar to the perovskite studied here. The values for t el reported 26 allows us to affirm that t el = 0.4 ± 0.2.…”

“…These researchers identified these materials as good high-temperature proton conductors. Thereafter, the corresponding application in solid oxide fuel cells (SOFCs) and other applications were proposed, and extensive research has been carried out in this field. − …”

Proton-Conducting Dense Ceramic Membranes for Hydrogen Separation

“…Proton-conducting dense ceramic membranes have become a promising group of inorganic membranes with high selectivity for hydrogen permeation [1][2][3][4][5][6] since Iwahara and coworkers discovered proton-conduction in SrCeO 3 based perovskite type ceramics in high temperatures in the 1980's [7] . The major problem with the SrCeO 3 based ceramic membranes is their low electronic conductivity, which leads to low hydrogen permeability.…”